Democrats remain confident there will be a GOP primary and believe Rounds has a glass jaw.

“Karl Rove and establishment Republicans think the fix is in for Mike Rounds but Jim DeMint and Chris Chocola have a different plan,” said Democratic Senatorial Campaign Committee deputy executive director Matt Canter. “We look forward to watching an epic tea party clash and supporting a strong Democratic candidate next year.”

Noem, who defeated Herseth Sandlin in 2010, promised to campaign hard for the GOP nominee.

“It is critical that we elect a Republican to the U.S. Senate in 2014 who will hold this Administration accountable, rein in wasteful spending and reduce our debt, and protect our liberties,” she wrote.